The present invention relates generally to high pressure and high flow liquid fluid hydrants used in the regulation of fluid flow, and relates more particularly to certain new and useful improvements in valve design and assembly.
As is well known to those engaged in the design and production of hydrants and hydrant assemblies, particularly valve body assemblies, it is necessary to provide systems which are compatible with fluid flow characteristics. This is done so as to minimize unusual effects such as chatter or turbulence during the operation of the fluidic system. When systems are relegated to low operating pressures, such adverse fluid flow characteristics are rarely present. However, when the system is to involve high pressures or high flow rates, turbulence is a frequent problem having significantly detrimental effect upon the overall system.
I have long been associated with the manufacture of hydrants such as are herein discussed. Currently, manmade snow is produced from water systems employing common hydrants. However, because of the need to use high pressure water, in rather significant volumes, standard hydrants possessing conventional plunger or gate valves are confronted with severe wear problems. These wear problems are characterized by moderate to severe corrosion on or around any surface at points of abrupt geometry change, such as discontinuations in linear surfaces or, at points at or near areas of cavitation or turbulence.
To attempt to use presently available valve bodies and tubing which would encourage high speed laminar flow would prove fruitless in the face of evidence which has clearly discloed that conventional valve parts are the root of the problem.
In addition to the corrosion precipitated by turbulence, other and more apparent nuisances also manifest themselves with the use of conventional valves and valve parts. For example, high pressure fluids effect a great pressure drop across an orifice and, in the case of a partially opened conventional valve, give rise to turbulence-caused vibrations. If a valve stem vibrates, an operator will observe the valve opening by itself. To thwart this characteristic, some manufacturers have attempted to lock valves. However, this approach is unsatisfactory because, in the artificial snow manufacturing environment, a frozen locking mechanism can present as much difficulty as a frozen valve.
High pressure/high flow can give rise to turbulence during initial operations that, in turn, invariably creates an excessive amount of corrosion on the valve surfaces immediately downstream of the valve seat. When one considers that these hydrants are placed below ground, it is intuitive that the turbulence and consequent corrosion presents a greater problem than vibration--frequent valve change requirements. One approach to limit vibration and the turbulence at the valve seat is by employing a complex internal fluid riser which is perforated and assembled in a caisson-like fashion, and which is drawn out of the valve seat. The valve stem, on which is mounted a washer-type apparatus, passes down through the major portion of the body and connects to the perforated riser. As the valve stem is withdrawn, successive numbers of perforations are exposed and the fluid flows through them in increasing amounts. This multiplicity of openings, in effect, avoids the abrupt pressure drop that takes place in conventional plunger or gate type valves. The difficulty with this type of mechanism arises in the event the perforations become plugged. Because of its design, with the flow always emerging from the topmost, exposed perforations, it is generally impossible to flush a plugged mechanism by merely opening the valve further. Thus, as mentioned above, in the process of snow making with such valves located far below grade, it becomes necessary to excavate.
The use of conventional valves is also disadvantageous in that the metal, (generally brass), under the turbulent conditions mentioned above, is found to corrode.
It is, therefore, an object of this invention to provide a new and improved high pressure liquid valve which can be used in hydrants of the type mentioned above.
Another object of this invention is to provide a new and improved valve washer which will be compatible with a valve seat formed of a non-corrosive material.
Another object of this invention is to provide a hydraulic valve washer which will give the effect, when opening, of a multi-apertured gate, and thus avoid abrupt and large pressure changes during initial fluid flow.
Another object of this invention is to provide a new and improved washer which will resist plugging and, in the event clogging or plugging occurs, be self-flushing.
Another object of this invention is to provide a novel valve washer seat that will resist corrosion and vibration whether under initial flow characteristics or full flow.
Objects and advantages of the invention are set forth in part herein and in part will be obvious herefrom, or may be learned by practice with the invention. The invention consists in the concept, novel parts, constructions, arrangements and improvements that are shown and described herein.